Railway traffic controlling apparatus



1942- R. ALLISOAJ 2,269,239

RAILWAY TRAFFIC CONTROLLING APPARATUS Filed July 27, 1940 HIS A I'TORNEY Patented Jan. 6, 1942 RAILWAY TRAFFIC CONTROILING:

' APPARATUS Leslie R. Allison, ForestHills, Pa., assignor to The Union Switch atv Signal Company, Swissvale,

. Pa., a corporation of Pennsylvania I Application July 27, 1940, Serial No. 347,969

'TClaims. (o1. 246-63) My invention relates to railwaytraffic controlling apparatus of'the class wherein traffic controlling means located on a locomotive orttrain is controlled by energy received from the trackway and the supply of energy from the trackway to the train is governed by traffic conditions in-advance of the train. More particularly,'- my invention relates to the train-carried portion of such apparatus.

In connection with systemsof the above-described class, it has beenproposed heretofore to provide the rails ofa trackway with'both track circuit current and loop circuit current. I The track circuit current'is supplied to the two rails connected in series so that the current flow in the two rails is in opposite instantaneous directions, while the loop circuit current is supplied to the two track rails in multiple so that the current flow in the two rails is in thesame instantaneous direction. The two trackway currents are supplied from a common source, and suitable apparatus controlled b-ytraffic conditions in ad- Vance is provided to control :the relative'in'stantaneous polarities of the two trackway currents, and at times to interrupt periodically-orecode-the supply of one of the two. currents. Cooperating with such trackway apparatus is suitable traincarried apparatus incorporating means arranged to be selectively responsive to therelative polarities and to the coded or non-coded {character of the two trackway currents.

above-described class is illustrated :and covered 'in Letters Patent of the United States No. 1,649,-"

629 granted to Herbert A. Wallace on November 15, 1927, for Railway traffic controlling. apparatus.

In the said patent, a three-position relay having two windings, one for each of the two track.- way currents, is employed and is proportioned to be responsive not only to the relative instantaneous polarities of the two trackway currentsbut also to the coded characterof the one coded trackway current. Ihave found that when such relay is employed in the above-described manner, it is necessary to code the one trackway. current at a relatively low frequency or rate because the No 1,649,629, by'providingnovel and'improved train-carried apparatus adapted to cooperate with the-trackway portions of a system of the'class described and incorporating means operated solely'by the receivedlportion'of the said one coded trackway energy. i

Another object of my invention is the provision in such train-carried apparatus, of a code following relay adapted to respond to relatively rapid code rates and to cooperate with the said three-position relay to selectively control trafiic governing means carried by the train.

A furtherobjectof my invention is to provide train-carried apparatus responsive to the'phase relation of the two trackwaycurrents and incorporating means responsive to a relatively rapid coding of one of the two trackway currents.

Anotherobject of my invention is the provision, insuch train-carried apparatus, of novel A system. :of the and improved means'toinsure against the threeposition relay responding to the periodic interruptions of the said one coded trackway current,

whereby to prevent unnecessary wear of theparts of such relay. p

A further object is to provide in train-carried apparatus responsive to the phase relation between the two trackway currents, additional means responsive to'one of the two currents coded at a, rat'elmore rapid than that at which the phase respbnsivdapparatus will respond,

thereby'enabling certain trains equipped with apparatus embodying my invention to detect a coding of the trackway'current and control an increased number of indications without afiecting the operation of trains equipped merely with phase-responsive apparatus.

l The above-mentioned .and other important objects and characteristic features of my invention which'will become readily apparent from the following description,'.are' attained in accordance with my invention by coupling a code'following 'relay to receive energy from the circuit supplying one of the two windings of the'three-position relay with the received portions of the one trackway energy that is at times periodically interrupted by the trackway apparatus. -I propose also to employ suitable decoding apparatus in connection with such code followingrelay, whereby to distinguish between the coded and noncoded character of the said onettrackway current, and to cooperate with the three-position relay, which is utilized solely to respondto the relative polarities of. the two trackway currents,

in selectively controlling a multiple indication train-carried signaling device. In addition, the

decoding apparatus may be employed to reduce the supply of the other or non-coded trackway current to its associated winding of the threeposition relay to a value such that operation of such relay is discontinued during the interval that coded trackway current is received by the train-carried apparatus.

I shall describe two forms of apparatus embodying my invention, and shall then point out the novel features thereof in claims.

In the accompanying drawing, Fig. 1 is a diagrammatic view illustrating a preferred form of apparatus embodying my invention. Fig. 2 is a diagrammatic view illustrating a modified form of the apparatus shown in Fig. 1, and also embodying my invention. Similar reference characters have been employed to designate corresponding parts in each of the two views.

Referring first to Fig. 1, the reference characters I and Ia designate the two track rails of a stretch of railway track divided in the customary manner into successive adjoining track sections, and provided with suitable trackway apparatus capable of supplying the rails I and Ia of each section with both track and loop circuit current and at times periodically interrupting the supply of one of such currents. Such apparatus might, for example, be similar to the trackway apparatus shown in Fig. 1 of the aforementioned Wallace Patent No. 1,649,629, wherein the supply of loop circuit current to the rails I and Ia is at times periodically interrupted through the medium of suitable circuit controllers, and the relative polarities of the track and loop circuit currents supplied to the rails I and Ia are controlled through the medium of suitable pole changers. In accordance with the existing practice, it is contemplated that the loop circuit current is interrupted or coded by the trackway apparatus at a relatively rapid rate, say at 120 or 180 times per minute.

The supply of track and loop circuit currents to the rails I and Ia is adapted to exert a control over the train-carried apparatus embodying my invention and illustrated in Fig. 1, through the medium of two magnetizable cores 3 and 3a mounted in front of the forward axle of g the locomotive and carrying windings 4 and 4a, respectively, disposed in inductive relationship with the rails I and Ia, respectively, and two additional magnetizable cores 5 and 5a mounted preferably in the rear of the forward axle of the locomotive and carrying windings 6 and 5a, re-

spectively, disposed in inductive relationship with the rails I and la, respectively.

The two coils 4 and 4a are connected in series in such manner that when voltages are induced therein by track circuit current flowing through the rails I and Ia in opposite instantaneous directions, such voltages are additive, and hence such coils function as the usual train-carried receiver for inductively picking up a portion of the track circuit current from the rails of the trackway.

The two coils 6 and Ba are connected in series in such manner that when voltages are induced therein in response to loop circuit current fiowing through the rails I and Ia in similar instantaneous directions, such voltages are additive. Coils '6 and 6a, therefore, function as the usual train-carried receiver for picking up a portion of the loop circuit current from the rails of the trackway.

The portions of the track and loop circuit currents picked up from the rails I and I a by the above-mentioned two receivers are supplied through amplifying means TA and LA, respectively, to windings 8 and '9, respectively, of a three-position two-element relay J. As shown, relay J is provided with condensers I0 and II connected in parallel with windings 8 and 8, respectively, to improve its operation.

Relay J further comprises a plurality of movable contact fingers I2, I3, I4 and I5. When the track and loop current receivers supply winding-s 8 and 9 of relay J with currents having a first predetermined phase relation, or in other words, the currents are of given relative instantaneous polarities, the fingers are swung to the right, as illustrated in Fig. 1, wherein contacts I2IB and 'I3-I I are closed. When the currents supplied to the two windings 8 and 9 of relay J by the receiver have a second predetermined phase relation, the fingers then are swung to the left, as viewed in Fig. 1, wherein contacts I2-I3 and I 3I9 are closed. For example, relay J may be so designed and constructed that when the current supplied from thetrack circuit current receiver leads the current supplied from the loop circuit current receiver by a first predetermined phase angle of substantially the relay then swings its movable contact fingers to their righthand positions, whereas when the current from the track circuit current receiver lags the current from the loop circuit current receiver by a second predetermined angle of substantially 90, the relay then operates its movable contact fingers to their left-hand positions. When the supply of current to either or both of the two windings 8 and 9 is discontinued, the contact fingers of relay J then assume a mid or deenergized position wherein contacts I l-20 and I5- 2I are closed. Preferably, the parts of relay J are so designed and proportioned that movement of the contact fingers to their mid positions is not effected by momentary interruptions in the supply of current to either winding 8 or 9. Relay J, therefore, does not follow the relatively rapid coding of the loop circuit current effected at times by the trackway apparatus.

To detect the coding of the one trackway current at times effected by the trackway apparatus, I couple a code following relay CPR to the receiver which picks up such coded current. One manner of coupling relay CFR to detect the coding of the trackway current is shown in Fig. 1, wherein there is employed a full wave rectifier R having its input terminals connected in series with condenser II of relay J and having its output terminals connected to relay CFR. Another manner of coupling relay CFR to detect the coding of the one of the two trackway currents is shown in Fig. 2, wherein relay CFR is shown coupled through a transformer CT to the receiver which inductively picks up from the trackway the coded one of the two trackway currents. This latter manner of coupling relay CFR will be described in detail hereinafter.

Relay CFR controls the supply of current to a center tapped primary winding 24 of a decoding transformer DT through the medium of a first contact member 25, and the supply of current from a center tapped secondary winding 26 of transformer DT to a slow releasing decoding relay DR is controlled by a second contact member 21 of relay CFR. It is evident that when relay CFR is steadily energized or deenergized, relay DR is released but when relay CFR. is responding to loop circuit current interrupted at the previously mentioned codes of or times per minute, relay DRthen is energized. Relay DR,

therefore, functions to distinguish between the coded and non-coded character of the loop circuit current.

The relays J and DR of Fig. 1 cooperate to selectively control a multiple indication traincarried signaling device, here shown as a fourindication cab signal CS. Cab signal CS comprises four lamps E, H, M and L, each when lighted capable of displaying a distinctive indication.

In describing the operation of the apparatus embodying my invention represented in Fig. 1, I shall assume that the apparatus is in its normal condition when the track and loop circuit currents received from the rails l and la have the first predetermined phase relation and the loop circuit current is periodically interrupted or coded. This condition of the apparatus is illustrated in Fig. 1, wherein relay J is shown with its contacts operated to their right-hand positions in response to currents having the first predetermined phase relation supplied to its windings 8 and 9, and relay DR is shown picked up in response to the periodically interrupted character of the loop circuit current. Under the abovementioned conditions, a high speed indication E of signal CS is caused to be displayed by a circuit which may be traced from terminal B of a suitable source of current, such as a battery not shown, through contact |2l6 of relay J, front contact 28 of relay DR, the filament of lamp E, front contact 29 of relay DR, and contact "-43 of relay J to the other terminal C of the source of current. p

When the currents supplied to relay J have the first predetermined phase relation but the loop circuit current is steady or non-coded so that relay DR is deleased, then lamp H of signal CS is illuminated over a circuit which extends from terminal B through contact l2-liiv of relay J, back contact 30 of relay DR, the filament of lamp H of signal CS, back contact 3| of relay DR, and contact l'|-l3 of relay J to terminal C.

If the currents supplied to relay J have the second predetermined phase relation, then relay J operates its contact members to the left as viewed in Fig. 1, and lamp M of signal CS is illuminated over a circuit passing from terminal B through contact lZ-IB of relay J, the filament of lamp M, and contact |9--l3 of relay J to terminal C.

Whenever the supply of either or both the track and loop circuit current to relay J is discontinued, as, for example, would happen if the locomotive carrying the apparatus of Fig. 1 follows another train in a section so that the track circuit current is shunted away from the track receiver of the locomotive, then relay J assumes its mid position and lamp L of signal CS becomes energized over a circuit extending from terminal B through contact l420 of relay J, the filament of lamp L of signal CS, and. contact 2l-l5 of relay J to terminal 0.

From the foregoing description, it is readily apparent that I have provided novel and improved train-carried apparatus wherein the three-position two-element relay J is required only to respond to the phase relations of the track and loop circuit currents, and the coded or non-coded character of one of the two trackway currents is determined by a decoding relay operated by a code following relay coupled with the circuit over which the coded one of the trackway currents is supplied to relay J. It can be seen, therefore, that since code following relay CFR is responsive to relatively rapid code rates,

such codes may be successfully employed in connection with the apparatus of Fig. 1. In addition, since relay J is not required to be responsive to the periodicv interruptions of the one coded trackway current, the life of such relay is considerably increased. I

It should, of course, be noted that relays J and DR may cooperate to control the usual whistle valve magnetusually provided in cab signal systems, and that the usual speed governor and cut-out relays, pilot relays, etc., may be provided to cooperate in the usual and well-known manner to control such magnet valves. Also, it should be noted that while for the sake of illustration a four-indication cab signal is shown'in Fig. 1 controlled by the decoding relay DR and the three-position relay J, a five-indication sig nal may, if desired, be controlled by the relays J and DR'shown in Fig. 1, an additional indication control being effected simply by providing a circuit including the left-hand contacts (l2l8 and Iii-I9) of relay J and front or back contacts of relay DR to one or another of two dis- I tinctive indications.

In Fig. 2, I have represented the apparatus shownin Fig. l modified to insure against any tendency of the three-position relay J attempting to follow the interruptions or code intervals of the coded one of the two trackway currents.

Referring now to Fig. 2, primary winding 33 of transformer CT is shown interposed in the connection of the amplifying unit TA of the track receiver to winding 8 of relay J. Secondary winding 34 of transformer CT is connected through the medium of rectifier R to code following relay CFR, and it follows that when the. track circuit current picked up from the trackway by the track circuit current receiver is coded, relay CFR is caused to operate and follow such coded current, but that when no track circuit current is being picked up, relay CFR is released.

Relay CFR controls the operation of code detecting relay DR in the manner explained in detail heretofore in connection with Fig-1. Relay DR, when picked up in response to relay CFR following code, controls means for causing the three-position relay J to'operate to its deenergized or mid position. As herein shown, such means comprises a front contact 35 of relay DR which when closed completes an easily traced shunt or short circuit path across the terminals of the two coils 6 and 6a of the loop circuit current receiver. It follows that when relay DR is picked up to shunt coils 6 and Ba, winding 9 of relay J is deenergized with the result that relay J is caused to operate its contact members to their mid positions.

The apparatus of Fig. 2 is in its normal condition, as shown in the drawing, when the coils 4 and 4a pick up coded track circuit current from the trackway. In this condition of the apparatus, code following relay CFR is caused to operate and follow the code impulses of track circuit current picked up from'the trackway; relay DR.

is picked up in response to the operation of relay CFR; front contact 35 of relay DR is closed to shunt coils 6 and 6a and as a result relay J is caused to operate to its mid position; and indication E of signal CS is illuminated over an obvious circuit which may be traced from terminal B through frontcontact 28 of relay DR, the filament of lamp E of signal CS, and front contact 29 of relay DR to terminal C. i

In. the eventthatthe track and loop circuit currents have the first predetermined phase relation or are of the given relative instantaneous polarities and the track circuit current is noncoded, relay CFR of course does not operate so that relay DR is released to open the shunt circuit connected across coils 6 and 6a. Relay J accordingly is caused to operate its contact members to their right-hand positions, and indicator H of signal CS is illuminated over a circuit extending from terminal B through back contact 3i of relay DR, contact |2l5 of relay J, the filament of lamp H of signal CS, contact I Y-I3 of relay J, and back contact 3| of relay DR to terminal C.

When the track and loop circuit currents have the second predetermined phase relation and the track circuit current is non-coded, relay J is caused to operate its contact members to their left-hand positions and indication M of signal CS becomes illuminated over a circuit which may be traced from terminal B through back contact 30 of relay DR, contact l2l8 of relay J, the filament of lamp M of signal CS, contact 19-43 of relay J and back contact 3! of relay DR to terminal C.

Whenever either or both of the track and loop circuit currents is absent from the trackway and is not picked up by the train-carried apparatus, relay J is deenergized and caused to operate to its mid position to complete for lamp L of signal CS a circuit which extends from terminal B through back contact 39 of relay DR, contact iii-20 of relay J, the filament of lamp L of signal CS, contact ii-l of relay J, and back contact 3i of relay DR to terminal C.

From the foregoing, it is readily apparent that when the train-carried apparatus of Fig. 2 is responding to coded track circuit current, relay J is in its deenergized position due to the fact that the loop circuit current is prevented from reaching winding 9, and as a result there is no tendency for relay J to attempt to follow the code intervals of the track circuit current. It follows, therefore, that the apparatus represented in Fig. 2 incorporates novel and improved means to insure against the three-position relay responding to the periodic interruptions of the one coded trackway current, thereby preventing unnecessary wear of the parts of such relay.

It should, of course, be noted that while the train-carried apparatus of Fig. 1 may be operated in response to the coding of either of the two trackway currents because the relays J and DR both cooperate in controlling the high speed or least restrictive signal aspects of signal C5, the apparatus of Fig. 2 may be utilized only with coded track circuit current if this coded current is to be employed to provide the high speed, least restrictive signal aspect. This results from the fact that in Fig. 2 the indicator E is controlled solely by relay DR which in turn is controlled by the coded one of the two trackway currents, and since the loop circuit current is not shunted away from a train by another train in the section, coded loop circuit current accordingly should not be employed to control the operation of relay DR.

A particularadvantage of apparatus embodying my invention and described heretofore is that by coding one of the two trackway currents at a relatively rapid rate higher than that at which a three-element relay such as relay J will follow the code, the apparatus embodying my invention may be utilized on certain trains or locomotives to detect the coding of such current as well as the phase relation of the currents to provide a greater number of indications in order that such locomotives may be operated at higher speeds, while other locomotives equipped with the usual cab signal equipment which detects only the phase relations of the two trackway currents may be operated over the same stretch of track without causing such apparatus to respond to the coding of the one trackway current. In this manner, therefore, trains operating at higher speeds may be provided with the additional indications necessary for such operation while low speed trains may be provided with only the usual or customary few indications required to control such low speed trains.

Although I have herein shown and described only two forms of railway trafiic controlling apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

l. Train-carried apparatus for use with a stretch of trackway supplied with two trackway currents one of which at times is coded and which currents comprise track circuit current supplied to the two track rails in series and loop circuit current supplied to the two track rails in multiple, the combination with two train-carried receivers one for said track circuit current and the other for said loop circuit current, and a threeposition relay having two elements selectively energized by said two receivers and which relay selectively operates to a first position or a second in accordance with the phase relation of currents in said two elements and to a third position when either of said two elements is deenergized, of a code responsive relay supplied with current from the one of said two receivers that picks up the coded one of said two currents, code detecting means controlled by said code responsive relay, means controlled by said code detecting means when detecting code for deenergizing one of said two elements of said three-position relay, and traffic controlling apparatus on the train controlled by said two-element relay and said code detecting means.

2. Train-carried apparatus for use with a stretch of trackway supplied with two trackway currents one of which at times is coded and which currents comprise track circuit current supplied to the two track rails in series and loop circuit current supplied to the two track rails in multiple, the combination with two train-carried receivers one for said track circuit current and the other for said loop circuit current, and a three-position relay having two elements selectively energized by said two receivers and which relay selectively operates to a first position or a second in accordance with the phase relation of currents in said two elements and to a third position when either of said two elements is deenergized, of a code responsive relay supplied with current from the one of said two receivers that picks up the coded one of said two currents, code detecting means controlled by said code responsive relay, means controlled by said code detecting means when detecting code for rendering the other of said receivers inefiective to energize the associated element of said three-position relay, and traffic controlling apparatus on the train controlled by said two-element relay and said code detecting means.

3. Train-carried apparatus for use with a stretch of trackway supplied with two trackway currents one of which at times is coded and which currents comprise track circuit current supplied to the two track rails in series and loop circuit current supplied to the two track rails in multiple, the combination with two train-carried receivers one for said track circuit current and the other for said loop circuit current, and a threeposition relay having two elements selectively energized by said two receivers and which relay selectively operates to a first position or a second in accordance with the phase relation of currents in said two elements and to a third position when either of said two elements is deenergized, of a code responsive relay supplied with current from the one of said two receivers that picks up the coded one of said two currents, code detecting means controlled by said code responsive relay, means controlled by said code detecting means in response to the coding of said one current for short-circuiting the other of said two receivers, and trafiic controlling apparatus on the train controlled by said two-element relay and said code detecting means.

4. Train-carried apparatus for use with a stretch of trackway supplied with two trackway currents one of which at times is coded and which currents comprise track circuit current supplied to the two track rails in series and loop circuit current supplied to the two track rails in multiple, the combination with two train-carried receivers one for said track circuit current and the other for said loop circuit current, and a twoelement three-position relay of the class caused to operate to a deenergized position when either element is deenergized and operated to one energized position or another according to the phase relations of currents in its two elements, said relay having a selected one of its elements con- A nected to the one of. said two receivers that picks up the non-coded one trackway'current, of a transformer having its primary winding connected in circuit with the other element of said three-position relay to the other of said two receivers, a code following relay connected to the secondary winding of said transformer, code detecting means controlled by said code responsive relay, means controlled by said code detecting relay in response to the coding of said one curstretch of trackway supplied with two trackway currents one of which at times is coded and which currents comprise track circuit current supplied to the two track rails in series and loop circuit current supplied to the two track rails in multiple, comprising the combination with two traincarried receivers one for said track circuit current and the other for said loop circuit current, of means responsive to the phase relations of currents in said two receivers, other means operable independently of said first means for detecting the coding of said one trackway current, means operable by said other means in response to the coding of said one trackway current for rendering said first-mentioned means incapable of responding to the phase relations of currents in said two windings, and train-carried traflic controlling means controlled by said first means and by said other means.

6. In combination with two train-carried receivers one arranged to pick up current flowing in opposite instantaneous directions and the other arranged to pick up current flowing in the same instantaneous direction in the two rails of a trackway for selectively operating a first relay to different positions in accordance with the relative polarities of the said picked-up currents, a code following relay coupled with a particular one of said two receivers for operation by the current picked up thereby when and only when such energy is periodically interrupted, means controlled by said code following relay in response to operation by the said coded energy for reducing the energy supplied from the remaining receiver to said first relay to a value insufficient to operate such relay whereby the relay is caused to assume a deenergized position, and railway traffic controlling apparatus selectively controlled by said first relay and by said code following relay.

7. In combination with two train-carried receivers one arranged to pick up current flowing in opposite instantaneous directions and the other arranged to pick up current flowing in the same instantaneous directions in the two rails of a trackway for selectively operating a three-position relay to one position or another according as said picked-up currents have one predetermined phase relation or another and to a third position whenever either of said currents is not supplied to said relay, a code following relay coupled with one of said two receivers for operation by the energy picked up thereby when and only when such energy is periodically interrupted, means controlled by said code following relay in response to the said coded energy for causing said first relay to operate to a third position, and railway traffic controlling apparatus selectively controlled by said first relay and by said code following relay.

LESLIE R. ALLISON. 

